Telephone system



2 Sheets-Sheet l Nov. 14, 1933. w. T. POWELL ET AL TELEPHONE SYSTEM Filed Feb. 6, 1932 Nov. 14, 1933.

w. 'r'. POWELL Er AL TELEPHorml SYSTEM Filed Feb. 6. 1932 2 Sheets-Sheet 2 A CORD CECLMT ALLOTTER INVENTORS Wx'nfrad T Powell D BY William J Vvlvl 'A oRY Patented` Nov. 14, 1933- ,f7UNITEDsT'ATEs' PATENT-worries. l

j 1,934,949 TELEPHONE SYSTEM Winfred T. Powell and William J. Vincent, Rochester, N. Y., assignors to The Stromberg- Carlson Telephone Manufacturing Company, Rochester, N. Y., a corporation'of New York Y Applieatio'n Fbrary je, 1932. 'serial 10,591,375

i 19 claims. (c1. 179-27) This invention relates to telephone systems,

and more particularly. to telephone systems ar-l also been expensive, while the service itself, since itv was not a part of the service provided by the telephone operating company, did not aord the high degree of accuracy and reliability aorded 20 in commercial telephone practice.

. In accordance with the present invention, a

novel arrangement is provided in a telephone system whereby such secretarialservice'may be supplied, on thepaymentof aprescribed-fee, in addif tion to the regular servicev offered-by the tele-l phone operating companies, and whereby the equipment affording such service, is designed for giving quick and reliable operation at a minimum of cost. f

an arrangement whereby a call to an unattended subscribers substation may be transferred to an answering secretarial deskv ofa telephone exchange wherein automatic switches provided on a percentage basis, reduce the number-of neces sary channels between a secretarys positionor positions at the telephone exchange and the lines of the subscribers entitled to such service.

A For a clearer understanding of the invention', 40 reference is made to the drawingsin which Fig. l is a schematic showing of the present invention; Fig. 2 represents the outline of an elevational view of a multiple switchboard including a patching position; Fig. 3 is a planview indicating the mechanical equipment of two secretarial positions; and Fig. 4 is a diagrammatic showing of a portion `of such a telephone system representing the detailed circuits thereof, which are particularly adapted for usenin providing cated three groups of telephone lines A, B and C with one hundred lines in each group, entitled to secretarial telephone service, although itwill be understood that the` number lof such groupsY and A further feature of the invention relates tor the secretarial service. v Referring especially to Fig. 1,`thereY are indi` the number of telephone lines in each group may be varied in accordance with the traffic requirements of each telephone system. At D there are indicated, jacks connected in multiple with other multiplejacksof these lines, and such a section 5 of a multiplevswitchboard 6 may be used `for this service, the jacks such'as D may be multiple calling. jacks in this section of the switchboard'. In this system there are provided so-called patch#- ing cords, such as E, whichrc'ords may terminate at one end in plugs for connection with the multiple jacks D and ,which'may terminate at the other end in the Vfixed contacts or terminals Vof a plurality of selectors or iinder switches `F which -arehe'reinrepresented as being ten number corresponding with percentage trunking familiar in automatic telephone exchange practice. If desired each patching cord may 'terminate at both ends .ina plug, in which case the connections from the iiXed contacts of the nder switches may terminate in jacksginto whichthe plug of one end of the patching cord may be inserted. The brushes' of each selector switch are connected by a trunk, such as H,vto a secretarial position, or positions I where this trunkfis pro- 8o vided with` listening and holding vkeys together with incoming and holding lamps, which will be hereinafter referredto. rAn allotterswitchjG is provided for each group of selector switches-for the purpose of assigning an idle selector switch for'use..r 'Y 1 It isbelieved that the invention will bestbe understood byv describing the manner in which the secretarial service is performed in the case of a call to'an unattended called line. Whenthe subscriberV entitled `to such servicer is about -to leave his office, he calls up ,thev telephone com` pany and gives the necessary instructions, whereupon a patching cord E is inserted-in a multiple jack of his line.' Thereafter wheny aparty at the substation of ak calling telephone line, such as 20, originates a call intended for such unattend ed line, the following' procedure takes place: When Vthe calling subscriber at substation 20 yinitiates the callV by removing his receiver from its switchj hook (not shown); the 'well-known line equipment (not shown) functions to light a lamp thereof andan A .operator inserts'theplug P ofV an idle cord circuit 21 into -the jack J of this calling line. 'This operator, using well-known equipment (not shown) associated with the cord circuit, inquires the number of the wanted telephone line and inserts the plug'P into-the jack J of this wanted subscribers line whereupon ring'- ing current is transmitted through both sides of 110 thersubscribers line in series, either automatically or in response to manually operated means. It has been pointed vout that this called subscribers line has been associated with one or more secretarial positions I, by connecting the patching cord E to a multiple jack of this line, so that whenringing current is applied to the terminals of the desired telephone line, this current is transmitted through the tip and ring contacts of the multiple jack D and the contacts of the plug of the patching cord, and thence through conductor 22 of the cord, winding of the relay 23, back Contact and armature of cut-off relay 24, condenser 25, and conductor 26 of the cord connected to the ring contact of the patchf ing plug, which completes this circuit. The relay 23 is operated and locked mechanically vvin response to this ringing current and at its righthand armature and contact completes a circuit from ground through the windingof group relay 27 to grounded. battery, which relay, it will be understood, is common to a group of patching cords E, the number of which in the present disclosure is ten., As soon as the group relay 27 is operated, it closes a circuittraceable from its grounded armature and front contact, winding of the slow releasing start relay 28,., armature and back contact of relay 28,' armature, back contact and Winding of the motor magnet 30 oi thev allotter to grounded battery which circuit energizes the start relay.V It will be understood that when the group relay 27 is operated it removes groundpotential from the group contact 31 of the finder switch.

VAs soon as the starting relay 28 is operated, it closes a circuit from groundits upper armature and front contact, Vallotter brush 33, conductor 34, back contact and armature of the `Vrotary starting relay 35, vertical off-normal contacts 36, winding of Ythe slow releasing, vertical starting relay 37, to grounded battery. This last named Vrelay on operating, closes a locking circuit for itself through its innermost front contact and armature andthe remainder of its original energizing circuit, which circuit is now independentV of the off-normal contacts 36.Y It shouldbe noted thatat thisgtime, the slow releasingrelay is short circuited, since bothof itsterminals are connected to ground, one of its terminals being connected to ground through the groupbrush 38 of the selector and the group contact with which it is in engagement and thence to grounded conductor 34; the other terminalV of the relay. 35 being connected to the ground conductor 34 through the rotaryoiT-normal contacts 39V which are closed until the tenth rotary step of the selector. With the rotaryV start relay 35 thus short circuited, it cannot operate, but the Vertical start relay 37 is operated to start the vertical movement of the selector switch. This is effected by operating the interrupter relay from grounded battery, its winding, armature and back contact of the vertical steppingniagnet 41, conductor 42, group brush 38 and the'group contact 31 with which it is in engagement, allotter brush, 33, front contact and armature Vof relay 28 to ground. The interrupter relay 40 thusattracts its arma-v ture and thereby closes a'circuit ,f from grounded battery, winding of the Vertical stepping magnet 41,` innermost front contactand armature of thev relay 40, middle, front contact and armature of relay 37, conductor 34, allotter brush 33, front Contact and armature of relay 28 to ground.' The steppingmagnet 4l`when operatedmoves the brushes 43, Vand the group. brush 33 of lthe selector one step in their vertical direction; also, when the stepping magnet 41 is energized it opens the circuit of the interrupter relay 40, which in turn opens the circuit of the stepping magnet 41. If the called line is not in the group thus selected, the group brush 38 will be in engagernent with a group contact similar to 31 which will be characterized by ground potential. As long as brush 38 encounters ground potential on its group contacts, relay 35 will be short circuited, and the vertical start relay 37 will remain operated through its innermost front contact and armature, while the circuit of interrupter relay 40 will be intermittently opened each time that the vertical stepping magnet 4l is group* of cords including the one connected to the called line, is reached by the selector brushes, the group contact 31. thereof will be characterizedby the absence of groundpotential, due to the fact that the group relay 27 is operated. As soon as the group brush 38 encounters this group contact 31', the interrupter relay .40 will remain inactive butthe rotary start relay 35, since it is no longer short-circuited, will be operated from ground, armature and front Contact of starting relay 28, allotter brush 33, conductor 34, rotary off-normal contacts 39, winding of rotary start relay 35, conductor 42,-back contact and armature of vertical stepping magnet 41, Winding of the interrupter relay 40 to grounded battery.,

The relay 35 is energized in the circuit, but the interrupter relay 40 is not operated, due to the resistance of` the relay 35 in series therewith. Relay 35 when it operates, opens a break point inthe operating circuit of the vertical start relay 37 so that this relay is disabled at this time, and no primary movement of the switch can be effected.

, It hasbeenmentioned that the vertical start relay 37 isslow releasing and it thereby introduces a delay sufficiently long to permit the selector brushes` to stop vibrating before their rotarymovement isv started. YWhen the relay 37 has released, it closes an operating circuit for the rotary stepping magnet 44, from grounded battery, resistance coil, front Contact and armature of relay 35, back contact, armature and windingof stepping magnet 44, outer front contact and armature of relay 35, armature and back Contact of relay 37, inner back contact and armature of relay to ground. The stepping magnet 44 is thus energized, but immediately interrupts its own circuit to step the selector brushes 43 intermittently until the test brush thereof encounters the test contact 46,

which ischaracterized by ground potential ap-l plied at the'right hand armature and front contact ofthe line relay 23. The presence of ground potential on this test contact, indicates that it is connected to the desired patching cord and the selector switch is broughtto rest with its brushes in engagement with the 'contacts of this cord. When this desired patching cord is selected, the stepping magnet 44 is short-circuited and the switching relay 45 is operated in a circuit, traceable from grounded battery, resista-nce coil, front contact and armature of relay 35, the back contacts and armatures in series of stepping magnet 44, through the low resistance winding of the relay 45 the test brush and the selected test Contact 46 with which it is in engagement, front contact and armature of relay 23 to ground.

The relay 45' on operation closes a circuit has beenfconnected.. The secretarial'operator,

'cuits the slow' releasing start relay 28,.which after a short interval retracts its armatures.

This interval is of such duration as to allow.

the'holding circuit including'theV high resistance winding of relay of the selector to be established before vthe holding Yground is disconnectedlat the upper armature and front con-V tactof relay 28. At the closeof this interval the allotter advances its brushes `to assign `an idle trunk for use since its magnet is intermittently Voperated from grounded battery, its

Ywinding back contact and armature, back con-` tact and armature of relay 28, brush 32, .front contacts and armatures of relays 45, at busy trunks, to ground. n t

The switching relay 45'v on operation also extends the connection thus far established including the conductors 22 and 26, through'the tip andY ring selector .brushes and through the tip and ring conductors 49 and 50 of the trunk, through theleft-hand windings Vof the repeating .coil 51,and thence in series through the high and Alow resistance windings of the `relay 52.

This relay is thus energized and, closes an operating circuit from grounded battery, windingV of the holding -relay.53, lowerfront contact and armature of relay 52, upperback contact and armature ofthe slow releasingrelay'54'to ground. As soon as the holding relay 53 is operated it completes a holding circuit for the selector and for the patching cord E, which circuitextends from grounded battery, resistor 55, inner armature and front contact of relayk 53, conductor 48, inner front contact,l armature and high resistance winding of relay 45, its lower inner front contact and. armature to ground. A circuit for holding the cut-oir relay 24of` the cord is com pleted in multiple with the circuit last described from ground, winding of the cut-oil relay, sleeve brush' of the selector switch, .upper innermost armature'and front contact of relay 45'to conductor 48. These last described circuits serve to maintain *the connection untilV the secretarial operator. has answered the call; f

The operation of the relay 53, 'completes a. cir

cuit from 'grounded battery left-hand winding of A .the relay 56, middle contact vand armature of relay 53,'lower-.righthandf winding of Vthe repeating coil-51, through the high resistance winding of relay 1.57 and through the low resistance winding of this relay inseries, upper right-hand winding of the repeating'coil,lowermost arma= from grounded battery; lamp 58, armature andY front contact of relay 57, back contact and armature of relay 59to ground.` 1

` The secretarial operator on noting the lighting of this lamp, actuates the listeningakeyto connect her telephone Aset 61 to thefconductors 62 and 63 of the trunk .to which the incoming call then inquiresas toy what subscriber was called and may convey to the calling party that the wanted subscriber is away from his oice, but will return at a certain time. In addition, the secretarialperator maykeep a record of the party calling this subscriber, which information may be transmitted to him when he returns to his oice. When the listening key 60 is actuated,

a holdingcircuit is closed for the slow releasing,V

holding relay 59 from grounded battery, 1winding of this relay, conductor 64, lower contacts.. of the listening key 60 to ground. The relay 59 on operation at rits upperarmature and front contact,. short-circuits the high resistance winding of the relay 57. With-this resistance removed fromY the circuitl of the relay 56, it operates and Y at its outer left-hand armature and front con tact, .short-circuits theihigh resistance winding of the relay 52, which results in `the tripping or'discontinuance of the application of ringing current to the called line in the well-known manner, and this relay is also effective in giving supervision also inthe well-known manner to theA operator. The relay'56 on'operation alsocloses a locking'circuit for. the holding relayr 53, ex-

tending from grounded battery, winding ofths relay, its Vupper front contact and armature, inner front contact and armature of relay 56 to ground. The relay 56 at its' right-hand armature and contact, closes a-circuit from ground, winding of the slow` releasing relay 54 to grounded battery.

When the listening key 60 is restored to normal, the secretarial operator, if she so desires, may hold the connection by actuating the holding key v73 since the. slow releasing relay 59 Y may have its circuit maintained either at the lower contacts 'of the listening key contacts of the holding keyr 73. f

60, or at the posed of a call, both the listening key 60 and the holding key 73 are restored to normal which results in the release of the slow releasing relay 59, which lin turn is effective to include the high resistance winding of relay 57 in the operating circuit of therelay 56. This last named relay thereupon deenergizes and at its right'hand ar.- mature and ground contact Veffects the release of the. slow releasing relay 54. Since the relay 56v releases quickly and since the relay 54 re-k leases slowly, there is an interval in which" the Vlocking circuit of lthe holding relay 53 is inter-V rupted soV that this relay releases. When, however, relay 54 releases, Yit again connects ground potential through its upper armature to its back Y contact in readiness for the next call. When the holding relay 53 deenergizes, it removes the holding battery from the conductor 48 which permits both the switching relay 45 and cut-oir relay 24 to release. When the relay 45 releases, it closes a circuit from ground, its inner arma.- ture and back contact, back contacts and arma` tures of relays 37 and 35,'vertical off-normalV .contacts 65, winding of the'release magnet 66r the Vlast mentioned connection, this Boperator restores the Ycord circuit used, to itsnormal condition.

f While ak selector having vertical and rotary.

movement has been disclosed and described, it will be understood that the invention is not limited to this type oi-switch, but other forms of switches and even relay .type selectors may be substituted therefor without departing .from the spirit of the present invention. `Wlflattvve claim is: v Y. v 1.v The method of handlingy telephone calls intended for unattended subscribers substations which comprises extending the 'telephone calls to the respective unattended substations, and` simultaneously and automatically non-numerically extending each such call over. one of a plurality of possible paths-.to a secretarial operator.

2. The methodoi handling telephone calls intended for unattended subscribers substations of group of substations, which comprises extending the telephone calls to the respective substations .and then automatically. and non-numerically extending said calls in succession to a 'i secretarial operator.

.3. The method oi handling telephone calls intended for unattended subscribers substations, which comprises extendingthe telephone calls to the respective substations and then extending 'i said calls automatically and non-numerically kto a secretarial operator through a number of channels less than the numberoi` said called sub stations.

4. The method of handling telephone `calls fj intended for unattended subscribers substations,

which comprises extendingsaid calls to said sub-l stations and completing the calls to a secretarial.

- operator automatically and non-numerically in response to the extension' of saidcalls to said Substations, through a number of channels less than the number of said substations.

5. The method of handling telephone calls intended fork unattended subscribers substations','

which comprises extending saidcalls to said substations, signalling said substations, and extending the calls to a secretarial operator automatically and non-numerically through a number of channels less than the number of said linesin response to saidsignalling.

6. The method of handling telephone calls mtended for unattended substations which cornprises `extending such calls tosaid unattended substations, and extending such calls to asecretary automatically and non-numerically over a number of channels vapproxin'iately equal tothe maximum number of probable simultaneous calls.

7. In a Vtelephone system,- a group of telephonelines, a group of unattended telephone lines, a secretarial position, means for interconnecting a line oi one group with a line or" va second group, andmeans including exclusively nonnumerical automatic switching means for extending such interconnected lines to said.secretarial position;

8. In a telephone system, a group of telephone lines, afgroup or" unattended telephone lines, a

secretarial position, means for interconnecting fa line of onel group with aline of the second group,

and exclusively non-numerical means including any one of a group of automatic switchesless than the-number of said unattended lines, for' extending said interconnected vlines to said Secre-1 ...itarial position., y

9. vIri a telephone'systeni, 'a group .of ktelephone lines, a group of unattended. lines, `asecretarial position, means for interconnecting aline ofone'L cluding a link circuit for establishing a Vportion of a connection from any of Asaid telephone .lines to` said auxiliary position prior'to theinitiation ofv a call intended for said telephone'line, and' non-numerical automaticswitching means for Aselectively connectingsaid auxiliary position to the link circuit associated Vwith said telephone line when called;

11. In a telephone system, a plurality of telephone lines, means for interconnecting said telephone lines; an auxiliary position, `link circuits connectible to said-telephone lines prior to the initiation of calls intended therefor, non-numerical switches to which said'link circuits are connected prior to the initiation of calls intendedfor saidtelephone lines, means rorconnecting non-numerical switches to said auxiliary position, and means responsive to the extension of a callgintended for one of said telephone lines for operating one of said non-numerical switches to extend the link ,circuit connected to said vlastnientioned telephone line, to said auxiliary position. Y f1 f 12. In a telephone system, a plurality of telephone lines, means for interconnecting saidtelephone lines, an' auxiliary position, link circuits L Vconnectibleto said telephone lines prior to the initiation of calls intended therefor, non-numerical switches to which said link circuits are connected prior to the initiation of calls intended for said telephone'lines, means for connecting non-numerical switches to said auxiliary position, and means responsive to the extension of aY call to one of said telephone lines for operating one of said non-numerical switches to extend the link circuit connected tosaid last-mentioned telephone line to said' auxiliary position, and allotting l means for'assigningidle non-numerical switches foruse in succession.

13. In a telephone system, a plurality of 'telephone lines, an operators position and a patchingv position, both havingY jacksvin which said telephone lines terminate, means including said operators position for interconnecting said teiephone lines, an auxiliary position, patching cords connectible to said telephone lines through the jacks thereof at said-patching position, and

means including a non-numerical switch operatedY responsive to the extension of a call to one of said telephone lines for extending the patching cord Y connected to said telephone line, to said auxiliary position.

14. In a telephone system, a plurality of telephone'lines, an operators position anda patching? position, both having jacks at which said telephone lines terminate, means including said operators position for interconnecting said telephone flinesfan' auxiliary position, .patching cords connectible to said telephone lines through the jacks thereof at said patching position, means includingnon-mnnerical switches operatline when called, means including a non-numeriing responsive to the extension of calls intended for said telephone lines for extending the patching cords connected thereto, to said auxiliary position, said non-numerical switches being equal in number to the maximum number of simultaneous calls extended through said patching cords,

and allotting means for assigning non-numericalv cal switch responsive to the action of said relay under the control of said ringing or signalling current for extending the patching cord connected Ato said called telephone line, to said auxiliary position.

16. In a telephone system, a plurality of tele- Vphone lines, an operators position and a patching position, both having jacks at which saidV telephone lines terminate, "patching cords connectible to the jacks'of telephone lines at said patching position, means including said operators position for interconnecting said telephone lines, an auxiliary position provided with a plurality of answering trunks, means including a non-numerical switch for extending an answering trunk to the patching cord of a telephone line on the extension of` a call to said telephone line, and an operators telephone set at said auxiliary position connectible to any of said. answering trunks. f-

18. In a telephone system, a plurality of telephone lines, an operators position anda patching position, both having jacks at which said telephone lines terminate, patching cords connectible to the jacks of telephone lines at said patching position, means including said operators position for interconnecting said telephone lines, an auxiliary position provided with a plurality of answering trunks, means including a nonnumerical switch for extending an, answering trunk to the patching cord of a telephone line on lthe extension of a call to said telephone line, an

operators telephone set at said auxiliary positionl connectible to any of said answering trunks, and means for maintaining the connection from the answering trunklto the patching cord of a called telephone line while said operators telephone set is connected to said answering trunk. r

19. Ina telephone system-av plurality of telephone lines, an operators position and a patching position, both having jacks at which said telephone lines terminatepatching cords connectible to the jacks of telephone lines at said patching position, means including said operators position for interconnecting said telephone lines, an auxiliary position provided with a p1u rality of answering ltrunks, means including a non-numerical switchr for extending an answering trunk to the patching cord of a telephone line on the extension of a callto said telephone line,

an operators telephone sei; at said auxiliary posi- 

